Safety means for nail guns



R. LAMOUREUX 3,032,768

SAFETY MEANS FOR NAIL GUNS May 8, 1962 2 Sheets-Sheet 1 Filed April 21, 1958 Imam/or:

170hild [81720217 652 May 8, 1962 R. LAMOUREUX SAFETY MEANS FOR NAIL GUNS 2 Sheets-Sheet 2 Filed April 21, 1958 hild jdlilflliifgl 3,032,768 SAFETY MEANS FOR NAIL GUNS Roland Lamaureux, 992 Thomas Chapais t., {Sh-Martin, Quebec, Canada Filed Apr. 21, 1958, Ser. No. 729,650 2 Claims. (ill. 1106) This invention relates to nail guns such as are used in the mechanical driving of nails and has special reference to safety means preventing injury to the operators of such nail or bolt guns.

One important object of the invention is to provide novel means for automatically closing the breech of the barrel of a nail gun upon the gun being in closed position and thereby preventing accidents to the gun user.

Another important object of the invention is to provide a novel means for coupling the breech closure of such a gun to the barrel under constant pressure and such as to compensate for wear after repeated closures of the gun.

A further object of this invention is to provide a clutch connection of novel character between the barrel and breech closure wherein the clutching is effected by linear movement of the closure into contact with the barrel breech and thereafter effecting rotation of the closure and effecting secure locking of the parts together.

A still further object of the invention is to provide a novel means whereby the closure is prevented from accidental opening after it closes the gun breech.

With the above and other objects in view, as will be presently apparent the invention consists in general of certain novel details of construction and combinations of parts hereinafter fully described, illustrated in the accompanying drawings and particularly claimed.

In the drawings like characters or" reference indicate like parts in the several views, and:

FIGURE 1 is a vertical longitudinal section along the axis of the gun with the breech open;

FIGURE 2 is a fragmentary plan view of the central part of the device with the breech closure in barrel closing position;

FIGURE 3 is a plan view of the gun in the position shown in FIGURE 1;

FIGURE 4 is a section on the line 44 of FIGURE 1;

FIGURE 5 is a longitudinal section along the axis of the gun barrel with the breech closed and taken on line 5-5 of FIGURE 9;

FIGURE 6 is a section on the line 6-6 of FIGURE 1;

FIGURE 7 is a fragmentary perspective view of the rear end of the gun barrel and the associated clutch elements;

FIGURE 8 is a detail perspective view of the forward end of the closure housing and showing the closure there- FIGURE 9 is a view on the line 6-6 of FIGURE 1 but showing the breech closure rotated through 45 and in its breech closing position;

FIGURE 10 is a fragmentary View partly in vertical section of the forward part of the closure housing, the breech closure being in closing position; and

FIGURE 11 is a perspective view of a cover plate used herein.

In the invention as herein disclosed there is provided a barrel 1 having an abruptly reduced forward end 1a providing a forwardly facing shoulder. The barrel end In is provided with a series of transverse openings 2 in its wall in order to dampen the sound effects in driving nails. The forward end of the barrel part Ia. is externally threaded as at 3 and on this threaded end is screwed a cap 4 having an external flange 4a. There is also screwed on this end a collar 4b which abuts against the cap 4. A second collar 40 abuts against the shoulder of the 3,32,?58 Patented May 8, 162

barrel and between the two collars 4b and 4c is supported a tubular member 6 which thus surrounds barrel end 1a in fixed spaced relation thereto. An outer tube 7 is slidably fitted on the tube 6 with its forward end around the collar 4b. The tube 7 has a reduced forward end 7a.

At 5 is a shield member having a circular body provided with a central opening fitting on the tube end 7a. This shield is held between the forward end of the tube 7 and the cap flange 4a.. A housing 9 is fixedly mounted on the barrel and this housing 9 is provided with an internal transverse rib 9a. The rear end of the tube 7 is bored to receive a coiled compression spring 8 which bears rearwardly against the rib 9a and thus resists rearward movement of the tube 7 and shield 5 so that the rim 5a of the shield can be pressed firmly against a wall during a nail driving operation thus protecting the Worker from injury by bent nails, splinters from the Wall and the like.

On the under side of the housing 9 there is provided a rearwardly open cylinder it having a diaphragm 10a at its forward end. Extending rearwardly from the cylinder 10 is a piston rod 11 the rear end of which carries a housing 12 containing the breech mechanism and other parts.

The forward end of the rod 11 is bored to receive a coiled compression spring 14 adapted, upon forward movement of the piston to engage the diaphragm Ida and act as a shock absorber. On the rear end of the housing 12 is fixed a closure from which depends a handle or grip l3. Projecting upwardly from the rod 11 is a spring socket 11a carrying a spring pressed latch member 15, a slot 16 being provided in the tube 9 to permit move-- ment of the socket. A groove 1b is formed in the rear end of the barrel 1 and in this groove is mounted an extractor element 17 having longitudinal sliding movement. The extractor is provided with a longitudinal groove 17:: and a stop pin 17b is carried by the housing 9 and extends into the groove to limit movement of the extractor. I

The general arrangement of the foregoing may be found in nail guns now on the market and what now follows relates especially to those elements and their combination which are novel in construction and partic ularly useful in carrying out the objects of this invention.

The rear end of the barrel 1 is provided exteriorly with four equally spaced and radially projecting lugs or teeth 18 lying in a common radial plane and the front faces 19 of which are inclined in such manner that the barrel end and lugs form an interrupted four entry screw thread, the back edge being rounded as at 20. In the housing 12 there is mounted for rotating and sliding movements at breech closure block 21 having a centrally disposed opening for a sliding hammer pin 22. The rear end of this pin extends into a chamber 23. In the chamber 23 a hammer head 24 is slidingly mounted, this head being formed on the forward end of a shank 24a. The pin 22 may be made integral with head 24. The rear end of the housing 12 is closed by a block 25 and fits within a chamber 13a formed in the upper part of the handle 13. The block 25 is provided with screw threaded openings 25a which receive the threaded ends of cap screws 26 the heads of which engage in sockets 13b formed in the handle. By this means the block 25 is secured within the housing 12. The shank 24a passes into and through the rear end of a recess or socket 251), and is provided on its rear end with a stop nut 24b thus limiting forward move ment of the hammer head 24. Surrounding the shank 24a is a coiled compression spring 24c one end of which seats in the socket 25b and, at its other end bearing against the rear face of the hammer head. This spring acts as a aosa'res (a shock absorber for rearward sudden movements of the head and serves also to cause the pin striking movement of said head for firing the gun.

Fitted within the housing 12 between the blocks 21 and 25 is a coiled torsion spring 27 which has its forward end secured to block 21 and rear end secured to block 25. The spring 27 is stressed to urge the breech block 21 forwardly and also to urge rotation of block 21 in a clockwise direction when seen from its front end. In the breech block 21 there is also formed a chamber 23 opening upwardly into the chamber 23. In the chamber 2% is pivotally mounted a scar 29 of angled shape and having an arm extending normally up into the chamber 23 and a second arm at its other end extending downwardly. This latter arm is engaged by a pin forced rearwardly by a spring 30 housed in the breech block 21. When in its normal position the arm extending into the chamber 23 lies forward of the head 24 and thus prevents it from striking the pin 22. Further the end of this arm is bevelled so that, after the head hits the pin relative forward movement of the block 21 leaves the sear free to tilt. A trigger 31 is pivoted at 32 in a slot 32a formed in the front edge of the handle 13. The trigger is held yieldably in forward position by a pin 33 urged forwardly by a spring (not shown) in a tube 330 fixed in the handle. In the housing 12 there is provided a slot 12:: through which a sear tripping lug 31a of the trigger projects. In the forward face of the block 21 is formed a cylindrical recess 34 opening forwardly into a square recess 25 providing four teeth 35a for engagement with the lugs 18 upon the gun being closed.

In the top of the housing 12 there is formed a slot the body of which extends longitudinally of the housing. This slot has an offset side extension itia shaped to provide a notch 41 in one edge. Screwed into the breech closure 21 is a cap screw 37 having a head of proper size to fit a slot 38 formed in a closure plate 39 which extends more than half way around the housing 12, the plate 39 being movable circumferentially on the housing. The cap screw 37 is substantially diametrically opposite the sear 29 with respect to block 25. The rear end of the barrel housing 9 is provided with a circumferential flange 42.

The gun has three positions, namely: an opened position in which the parts are as shown in FIGURES 1, 3, 4 and 6, a closed position in which the parts are as shown in FIGURES 2, 5 and 9, and a cocked position to be described hereinafter.

In the opened position, the barrel assembly may be rotated about a quarter turn around piston rod 11 to clear the breech block assembly and enable loading of the gun. Also, in the opened position, the breech block is urged and maintained by spring 27 in forward limit position with respect to housing 12 and is also retained in anticlockwise limit position against the action of the same spring 27, because screw 37 is engaged in notch 41 as shown in FIGURES 2, 4 and 6. Thus, the sear 29 is in an inclined plane which does not coincide with the plane containing trigger lug 31a.

To close the gun, the barrel and breech are simply brought and pressed together whereby locking of said parts takes place automatically: the lugs 18 pass freely through square recess 35 with which they are in alignment as shown in FIGURE 6 and enter circular recess 34; at this time, flange 42 pushes rearwardly on block 21 and the head of the screw 37 is released from the notch 41 whereby spring 27 urges clockwise rotation of breech block 21 from the position shown in FIGURE 6 to that shown in FIGURE 9, so that tight coupling takes place caused by engagement of the inclined front faces w of lugs 18 with the back faces of teeth 35a. In the interlocked position of the barrel and the breech block, the screw 37 is in the position shown in FIGURE 2, wherein it is noted that said screw is still spaced from the adjacent longitudinal edge of slot 40. This allows breech block 21 to rotate further if required, in order to compensate for wear of the locking faces of the closure. Thus, secure and tight locking of the parts is always obtained despite wear resulting from prolonged use.

In the closed position, the sear 29 lies in the plane of the trigger lug 31a but is spaced forwardly thereof.

Cooking of the gun is obtained by pressing said gun with the shield 5 against a surface whereby barrel 1 and breech block 2i remains stationary and the tool housing moves forwardly over the barrel against the action of springs 5 and 27. Upon abutment of hammer head 24 with sear 2?, further forward movement of the housing and associated block 25 compressibly loads hammer spring 240. In the fully cocked position, breech block 21 practically abuts against block 25 and lower arm of scar 29 contacts trigger lug 31a. A pull on the trigger 31 will now cause the sear 29 to pivot and release the hammer head 24 which will move forward and cause the pin 22 to fire the gun.

To open the gun, the closure plate 39 is rotated anticlockwise to thereby rotate the breech block 21 from position of FIGURE 9 to the position of FIGURE 6, thereby unlocking the barrel and stressing spring 27 in torsion. The screw 37 moves from position shown in FIGURE 2 to the position shown in FIGURE 3 wherein it is held engaged within notch 41 by the forward force of spring 27.

Although a specific embodiment of the invention has been illustrated and described, it will be understood that various alterations in the details of construction may be made without departing from the scope of the invention as indicated by the appended claims.

What is claimed is:

1. In a nail gun, a hand grip carrying housing having a forward opened end, a tubular member pivotally connected to said housing and mounted forwardly of the same, a barrel mounted for longitudinal non-rotatable movement within said tubular member, said barrel having an opened rear breech end, clutch elements formed on said end, a breech closure mounted in said housing for longitudinal and rotative movements relative to the barrel and housing, clutch elements carried by the breech closure and cooperative with the clutch elements on the barrel for interlocking the barrel and breech closure upon rotation of the latter, spring means in said housing attached to said housing and said closure, operable to urge longitudinal movement of said closure forwardly in said housing into a forward limit position adjacent the forward end of said housing and operable to urge rotative movement of said closure with respect to said housing from a barrel releasing position in which the clutch elements of said barrel and closure are in mutually releasing angular position, into a barrel locking position in which the clutch elements of said barrel and closure are adapted to interlock, latch means automatically operable to latch said closure in barrel releasing position and against rotative movement under the action of said spring means upon said closure taking said barrel releasing position, said latch means being inoperable for longitudinal positions of said closure other than said forward limit position.

2. In a nail gun as claimed in claim 1, wherein said latching means include a radial projection on said closure, an L-shaped slot in said housing for the passage of said projection and a notch in the forward edge of the transverse leg of said slot, whereby said spring means urge said projection against the forward edge of said slot and rotation of said closure will cause engagement of said projection within said notch, rearward movement of said closure under action of said barrel causing release of said projection from said notch and interlocking rotation of said closure under action of said spring means and a cover plate surrounding and in sliding contact with said housing for manual rotating movement with respect to said housing, said cover plate having a longitudinal slot slidably receiving said projection whereby rotation of said cover plate will cause rotation of said projection and of said closure, said cover plate allowing longitudinal movement of said projection and of said closure with respect thereto.

References Citea: in the file of this patent UNITED STATES PATENTS 6 Phillips et a1 Apr. 10, 1956 Skumawitz Dec. 29, 1959 Kopf et al. July 19, 1960 FOREIGN PATENTS Australia. Nov. 7, 1956 Great Britain Jan. 2, 1957 France June 30, 1954 France Feb. 27, 1956 

